Contents: Fuel pump ⇊ Pressure regulator ⇊ Injector ⇊ Resistor ⇊ Main relay ⇊ Precautions when performing…⇊
Fuel pump
Fuel enters the pump through the fuel filter, flows around the anchor through the one-way valve and enters the engine compartment. A muffler is used to dampen pulsations in the fuel flow. The pump has a safety valve to relieve excess pressure. It opens in cases of flow blockage in the outlet channel. When the safety valve is open, fuel flows from the high-pressure section to the low-pressure section. There is also a check valve to maintain high fuel pressure in the outlet channel after the pump is switched off, which makes it easier to restart the engine.
Pressure regulator
The fuel pressure regulator maintains constant fuel pressure in the injectors. The chamber, which contains a spring that creates pressure, is connected to the air intake manifold. This allows maintaining constant fuel pressure at 2.55 atm above the manifold pressure. When the pressure difference in the top-beer channel and in the manifold exceeds 2.55 atm, the diaphragm is pushed forward and excess fuel flows back into the gas tank through the return line.
Injector
The injector is a constant-stroke axial device actuated by a solenoid. The injector consists of a solenoid, a plunger, a needle valve, and a housing. When an electric current is passed through the solenoid coil, the valve is lifted, and fuel under pressure enters the injector and then to the inlet valve. Since the fuel pressure and the lift of the needle valve remain constant, then when the needle valve is lifted, the amount of fuel injected is determined by the duration of the valve opening, i.e., the duration of the current passing through the solenoid coil. The injector is sealed at the top and bottom with O-rings. These rings also serve to muffle the noise of the operating injector.
Resistor
The injection adjustment, i.e. the moments of opening and closing the injector, must be very precise, as this determines the proportion of the air-fuel mixture. In addition, the injector must have a long service life. To achieve maximum injector response speed, it is necessary to reduce the current rise time at the moment of supplying voltage to the injector coil. Therefore, the number of turns in the coil is reduced to a minimum with a circuit for reducing the coil inductance. On the other hand, because of this, the coil has low resistance, which leads to large currents flowing through the coil. As a result, a significant amount of heat is released in the coil, which reduces the service life of the injector. To reduce the current flowing through the coil, a limiting resistor is installed between the voltage source and the coil.
Main relay
The main relay is a direct connect type and consists of separate relays to supply power to the ECU and the fuel pump. The relay is mounted at the rear of the fuse box.
Precautions when performing maintenance
- Do not operate the fuel pump when there is no fuel in the lines.
- Fuel hose clamps should not be reused.
- It is necessary to check that all multi-wire connectors of the ECU are securely fastened. Poor electrical contact can lead to high voltage being supplied to the coil and capacitor, which will cause the integrated circuits to burn out.
- During maintenance, keep all ECU module parts and connector contacts dry.
- Before disconnecting any components, turn off the ignition and disconnect the battery ground cable.
- Use only 12 volt battery as power source.
- Do not disconnect the battery cables while the engine is running.
- Do not press the accelerator pedal while starting the engine.
- Do not give the engine high revs immediately after starting, or immediately before turning off the engine.
- Do not supply power to the injectors directly from the battery.
[Material obtained from the website hondabook.ru]